1. Field of the Invention
The present invention relates to a solid oxide fuel cell device, and more particularly to a solid oxide fuel cell device for generating electricity in an amount proportional to required power, by reacting fuel with a generating oxidant gas.
2. Description of the Related Art
Solid oxide fuel cells (“SOFCs” below) operate at relatively high temperatures, using an oxide ion-conducting solid electrolyte as an electrolyte, with electrodes placed on each side thereof, and with fuel gas supplied to one side thereof and oxidant (air, oxygen, or the like) supplied to the other side thereof.
In such SOFCs, steam or carbon dioxide is produced by the reaction between oxygen ions passed through the oxide ion-conducting solid electrolyte and fuel, thereby generating electrical and thermal energy. The electrical energy is removed to outside the SOFC, where it is used for various electrical purposes. The thermal energy is transferred to the fuel, the SOFC, the oxidant, and the like, and is used to raise the temperature thereof.
Japanese Patent Unexamined Publication No. 2007-103194 (JP2007-103194A) sets forth a power supply furnished with a solid oxide fuel cell. In the fuel cell device set forth therein, fuel and air are combusted in a combustion chamber after contributing to the generation of electricity, and that heat of combustion is used to heat the cell stack.
Japanese Patent Unexamined Publication No. 2009-32555 (JP2009-32555A) sets forth a fuel cell device. In this fuel cell device, a fuel gas supplying reformer and fuel cell units are raised to a predetermined temperature in a startup stage. In this startup stage, switching off between a partial oxidation reforming process (POX), an auto-thermal process (ATR), and a steam reforming process (SR) occurs as the temperature rises within the reformer, thereby reforming the fuel.
Furthermore, in the fuel cell device set forth in JP2009-32555A, control is executed so that electrical generation by the cell stack is begun when the cell stack temperature reaches a temperature at which electrical generation can be started, and electricity is generated while a predetermined flow quantity of fuel gas supplied to the reformer and oxygen-containing gas supplied to the cell stack continue to be supplied during an interval between surpassing the temperature at which electrical generation can start and the elapse of a predetermined time. Sufficient electricity is thus obtained when the load-following operation is started following the end of the continuous supply of a predetermined flow quantity.